15.1.2. Core Interfaces

Try these first

1. 1.

   What is the main purpose of the Collection interface?

   Hint

   Think of the Collection interface as a foundation.

2. 2.

   What type of elements does a Set store?

   Hint

   Focus on the definition of a Set.

3. 3.

   What does the Collection interface represent?

   • A group of elements
   • A single element
   • An ordered list

   Hint

   Think of what Collection means in programming.

4. 4.

   True or False: A Set allows duplicate elements.

   • True
   • False

   Hint

   Recall the distinguishing feature of a Set.

5. 5.

   Create a Java program that uses a List to store the names of students enrolling in a course, and demonstrate the ability to manage duplicates.

   Hint

   Use an if-condition to check for existing names before adding a new one.

6. 6.

   Implement a scenario using a Map to store a phone book, where user names are keys and phone numbers are values. Create methods to add, retrieve, and delete entries.

   Hint

   Remember to ensure that each user name is unique.